UPS Sizing Calculator

Determine the right VA (Volt-Ampere) rating for your Uninterruptible Power Supply (UPS). Perfect for bridging the gap before a standby generator turns on.

Convert Horsepower (HP) to Watts (W) easily. Useful for sizing generators and understanding power requirements.

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Power Input

Recommended UPS Rating

1000 VA

Minimum Required: 833 VA

Understanding UPS Sizing

An Uninterruptible Power Supply (UPS) is rated in Volt-Amperes (VA), whereas most electronic equipment is rated in Watts (W). The relationship between the two is defined by the Power Factor (PF).

For sizing a UPS for typical computer and networking equipment, a power factor of 0.6 is commonly used as a safe, conservative estimate.

  • Minimum VA = Total Watts / 0.6
  • Recommended VA = Minimum VA + Future Expansion Margin (typically 20%)

Note: Higher-end UPS systems (like pure sine wave units) might have a higher power factor closer to 0.8 or 0.9. However, using 0.6 ensures you don't undersize standard line-interactive units.

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